SLD Architecture for Netweaver Landscape

Hello,

We are doing a Netweaver implementation involving BW-SEM, Enterprise Portal & XI. For XI, SLD is anyways mandatory.

Whether an SLD is required for EP. If yes, then what is the recommended architecture for SLD for the entire landscape?

Also, should we have a separate landscape for DEV/TST & PRD or one single SLD. Should it be hosted on a separate machine or on any of the servers hosting these components.

Regards,

Manas